In order to treat various diseases caused by abnormal function of immunity, various pharmaceutical agents, which are generally referred to as immuno-regulators, have been developed. The term "immuno-regulator" as used herein signifies agents for recovering immuno-reaction from its abnormal fall and suppressing its excessive acceleration in order to maintain normal function of immunity. As the agents belonging to such category, there have been developed various types of agents including levamisol (Aldrich Corporation). However, these conventional immuno-regulators are derived from chemical materials but not from biological materials, so that their dangerous side-effects can not be completely eliminated. In fact, significant side effects have been reported for some immuno-regulators.
Essentially the immuno-reaction has physiological function for maintaining homeostasis, which is supposed to be regulated by physiologically active substances contained in a living body.
Accordingly, an object of the invention is to provide an immuno-regulator of physiologically active substance having less side effects in lieu of conventional chemical substances.